Dynamic-Wallpapers

Resources and how-to intended for my memory, mostly.
Animated ( well… rather slow transitionning ) backgrounds for Gnome desktop environment in my « pro » machines.
I only show here personal, non branded material, free for any usage.
Tested on Ubuntu 22.04 and 22.10




← .deb available, see latest release !
Those gif of course do not reflect the real duration and smoothness of transitions. Transitions are very smooth.

Roles of files and folders

Gnome Control Center ( settings ) looks into
/usr/share/gnome-background-properties ( system side for all users )
and
$HOME/.local/share/gnome-background-properties ( user's side only )
for a « pointer » .xml file in order to offer its referenced slideshow(s).

This « pointer »

• can be named whatever you like but must be into a gnome-background-properties folder
• contains amongst other things the path to the « description » of the slideshows and eventually the list of pictures for a slideshow ( not mandatory )
• may list many slideshows,
• is a rather short file ( if you don't list all the pictures in it. )

The « description » .xml file targeted by the « pointer »

• can be named and located however you like - as long as it's referenced accordingly into the « pointer »
• contains the full scenario for your slideswhow, paths to the needed pictures, durations for static picture and transitions from a picture to another
• gives the whole duration of the slideshow ( sum of all durations, static + transition )
• sets a start time, synchronized with your system time so slideshows can act ± as clocks or match day and night, or seasons or events…
• may be a long file ( depending on how many pictures involved in the slideshow. )

Other helpful notes

Regarding elements involved in a slideshow ( both .xml files + pictures )

• if saved only system side for all users to access, they must bear read right for others - owned by root:root with 644 on files, 755 on parent directories
• if saved only one user's side - owned by $USER:$USER with 640 on files and 750 on parent directories should be enough
• therefore if a « pointer » and/or a « description » are saved system side targeting elements saved user's side, those latter elements and parent directories should bear read right for others ( while owned by $USER ).

Regarding marks in .xml files

• paths to files <filename> <file> <from> <to> are absolute, full letters typed, no $HOME nor ~ nor ../ there and no need for escaping space character in paths ( no " nor ' nor \ there )
• in « pointer » there must be a different <name> for each « description »
• absence of <static> crashes gnome-shell but
• absence of <transition> seems ok, so carefully prefer keeping all marks while setting 0.0 values
• launch gnome-control-center from terminal to check your .xml files, it will spot issues ;-)

Beware the future of these slideswhows in Gnome may be uncertain

they still work this way in Ubuntu 22.04,
where you have the ability to set a still ( or animated ) background per style of theme, one for light and one for dark.
They still work so far in 22.10 too where the shift between dark and light mode is held a bit differently.